Darkroom only works for a few seconds.

I see that other users reported this as well;
the problem is that darkroom mode only works correctly for around 5 seconds, then the display is not inverted anymore but the red filter remains (so white becomes red, black text on red background).

Nubia Z11 (NX531J)
Android 6.0.1
f.lux version 22
compositor driver

will be updating to the beta to see if that changes anything. any help is appreciated.